Identifying phantom images generated by side-lobes

A method of generating an impact report for a mask layout during simulation based checking, the method comprising:

• dissecting the mask layout and placing evaluation points on segments of the dissected mask layout;
• performing one of sizing up features in the mask layout by a predetermined amount and computing rings for the features in the mask layout;
• counting overlap areas caused by one of the sizing up and the computing rings;
• and
• if a total weight of an overlap area exceeds a trigger weight, then adding an evaluation point to the overlap area;
• simulating a wafer image of a portion of the mask layout;
• comparing the simulated wafer image with the dissected layout including any additional evaluation points;
• and
• outputting the impact report based on the comparing.

A mask layout impact report comprising:

• a plurality of evaluation point locations;
• and
• a corresponding plurality of deviations for the plurality of evaluation points,
• wherein at least one deviation indicates a difference between a desired feature location on a wafer and a corresponding simulated feature location, and
• wherein at least one other deviation indicates a phantom image that represents an undesirable, simulated feature on the wafer with no corresponding feature on the mask layout.

An automatically generated mask layout file including potential locations of phantom images, a phantom image representing an undesirable feature on a wafer with no corresponding feature on the mask layout, the mask layout file generated by:

• performing one of sizing up features in the mask layout by a predetermined amount and computing rings for the features in the mask layout;
• counting overlap areas caused by one of the sizing up and the computing rings;
• and
• if a total weight of an overlap area exceeds a trigger weight, then adding an evaluation point to the overlap area to identify that location as a potential location of a phantom image.

A method of eliminating phantom images created by features in a mask layout, the method comprising:

• performing one of sizing up features in the mask layout by a predetermined amount and computing rings for the features in the mask layout;
• counting overlap areas caused by one of the sizing up and the computing rings;
• if a total weight of an overlap area exceeds a trigger weight, then adding an evaluation point to the overlap area to identify that location as a potential location of a phantom image;
• simulating a wafer image of a portion of the mask layout including the evaluation point;
• and
• if a phantom image is generated at the evaluation point on the simulated wafer image, then providing a transparent area on the mask layout at the evaluation point, wherein light transmitted by the transparent area is approximately 180 degrees out of phase relative to light transmitted by features on the mask layout.

A method of eliminating phantom images created by features in a mask layout, the method comprising:

• performing one of sizing up features in the mask layout by a predetermined amount and computing rings for the features in the mask layout;
• counting overlap areas caused by one of the sizing up and the computing rings;
• if a total weight of an overlap area exceeds a trigger weight, then adding an evaluation point to the overlap area to identify that location as a potential location of a phantom image;
• simulating a wafer image of a portion of the mask layout including the evaluation point;
• and
• if a phantom image is generated at the evaluation point on the simulated wafer image, then providing a transparent area on the mask layout substantially adjacent the evaluation point,
• wherein light transmitted by the transparent area is approximately a same phase relative to light transmitted by features on the mask layout.

A method of identifying potential locations of phantom images from a mask layout, the method comprising:

• performing one of sizing up features in the mask layout by a predetermined amount and computing rings for the features in the mask layout;
• counting overlap areas caused by the sizing up;
• and
• if a total weight of an overlap area exceeds a trigger weight, then adding an evaluation point to the overlap area to identify that location as a potential location of a phantom image.